Abstract: An information recording medium includes a substrate and a recording portion having recording layers on the substrate, wherein the recording portion is capable of three-dimensional recording by changing an optical constant of the recording layers by irradiation of recording light, and a first reflected-light reducing portion for reducing reflected lights of reproducing light from the substrate side is provided at a side opposite to an incident side of the reproducing light with respect to the recording portion, and an optical information recording/reproducing apparatus records and reproduces information to and from the medium.

Abstract: An electronic device that performs at least reading or regeneration of data in or from a hologram disc is characterized by including an objective lens 11 disposed opposite a hologram disc (MH) 1; a laser light source 5 that emits a beam toward the objective lens 11; and a light receiving element 17 that receives a beam reflected from the hologram disc (MH) 1 by way of the objective lens 11, wherein a corner cube array 8 that reflects a portion of a beam traveling from the laser light source 5 toward the objective lens 11 is interposed between the laser light source 5 and the objective lens 11.

Abstract: The present invention is intended to provide optical recording media of hologram type capable of high-density recording and capable of preventing noise even when the informing light and the reference light leak from filter layers formed of wavelength-selective reflection films. Accordingly, the present invention relates to optical recording media has a first substrate, a recording layer, a filter layer, an optical absorption layer and a second substrate in this order, wherein the recording layer records information by use of holography; methods of producing the same, as well as optical recording methods for the recording media and optical reproducing methods. Preferably, the optical absorption layer absorbs a light having a wavelength within 350 nm to 600 nm and transmits a light having a wavelength within 600 nm to 900 nm.

Abstract: A hologram recording/reproducing apparatus records data as a hologram by applying signal and reference light beams to a hologram-recording medium, obtains a diffracted light beam by applying a reproduction light beam to the hologram, and reproduces the data using the diffracted light beam. The hologram recording/reproducing apparatus includes an external-cavity light source, a polarization-control element that changes a polarization angle of a light beam emitted from the external-cavity light source, a polarizing-beam-splitting element that splits the light beam to obtain two light beams and that changes a ratio between amounts of the two light beams, a photoreceptor that receives one of the two light beams, a spatial light modulator that receives the other beam and that generates signal, reference, and reproduction light beams, and a control unit that changes the polarization angle or polarization state of the light beam.

Abstract: Provided is an optical information recording method and an optical information recording medium, which can achieve easy duplication in holographic recording. The optical information recording method is for recording information to an optical information recording medium 4 which includes an information recording layer to which information is recorded using holography. In the method, virtual information light 6 composed of information light 2 to which information is added by spatially modulating at least a part of light ray flux emitted from a light source and of recording-specific reference light 3 is generated, and virtual information light 6 and virtual recording-specific reference light 8 are irradiated onto the information recording layer so that information is recorded thereto by interference pattern generated by interference between virtual information light 6 and virtual recording-specific reference light 8.

Abstract: A data page for use in a holographic data storage system, and to a method and an apparatus for writing to holographic storage media using such a data page are described. The data page has dark zones for each boundary between phase blocks of a phase mask of the holographic data storage system, which consist of switched-off pixels that are not used for encoding data, and which coincide with the boundaries between the phase blocks.

Abstract: An optical disc apparatus reproducing information on the basis of a standing wave recorded on a disc-like volume type recording medium includes: a first focus position adjusting unit configured to adjust the position of a focus on which a first light beam focuses inside a recording layer inside the volume type recording medium in the optical axis direction of the first light beam; a second focus position adjusting unit configured to adjust the position of a focus on which a second light beam focuses inside the recording layer in the optical axis direction of the second light beam; a controller configured to control the first focus position adjusting unit and the second focus position adjusting unit; and first and second detectors configured to detect the first and second reproduction light beams.

Abstract: A method of storing data includes receiving general purpose (GP) data and special Error Tolerant or Streaming (ETS) data, storing the GP data using a data storage method, and storing the ETS data using a different data storage method which affects the access rate, resilience to errors, data integrity, storage density, or storage capacity. The storage medium, which can include a disk drive, flash memory, or holographic memory, is utilized differently depending on the required Quality of Service in aspects including block size, storage of error correction codes, utilization of error correction codes, storage area density, physical format pattern, storage verification, or reaction to failed storage verification. For disk drives these differences include spacing between tracks; overlap between tracks; spiral track formatting; concentric track formatting, and size of blocks, and for flash memories these differences include levels per cell and number of cells.

Abstract: An apparatus for recording/reproducing holographic data and a method of adjusting a position of a recording layer. While an objective lens focusing first and second lights having different wavelengths on a holographic data storage medium including first and second reflective layers reciprocatingly moves in a direction of an optical axis, a focus movement unit, which moves a focus of the second light in the direction of the optical axis until a time difference between a first detection signal generated when the first light is reflected from the first reflective layer and a second detection signal generated when the second light is reflected from the second reflective layer becomes a value corresponding to a position of a desired recording layer, is controlled to move a focal position of the second light so that the focal position of the second light can be adjusted to the position of a desired recording layer.

Abstract: A holographic optical information recording/reproducing device is provided with a laser light source 1 and a polarizing beam splitter 8 for splitting a light from the laser light source 1. At the time of recording information, one of light beams split by the polarizing beam splitter 8 is modulated by a spatial light modulating element 2 to form a beam array, which becomes a signal light 25, whereas the other split light beam becomes a reference light 22. Interference fringes generated by the signal light 25 and the reference light 22 are recorded as holograms in a holographic disc 5. At the time of reproducing the information, only the reference light 22 is irradiated to the holographic disc 5 and its diffracted light is detected.

Abstract: A hologram recording method is a method of recording a hologram, on a hologram recording apparatus that records information by forming a diffraction grating through oppositely irradiating the signal beam and the reference beam to the hologram record carrier.

Abstract: A hologram recorder includes a light source for emitting a laser beam, a polarizing beam splitter for splitting the laser beam into a recording beam and a reference beam in accordance with a state of polarization, and a rotary polarizer located between the light source and the polarizing beam splitter. The rotary polarizer has the function of optical rotation, whereby a polarization component to be the recording beam is increased from the central portion toward the peripheral portion of the laser beam, and a polarization component to be the reference beam is decreased from the central portion toward the peripheral portion of the laser beam.

Abstract: An optical information recording/reproducing apparatus includes an optical mechanism that collects an information beam and a reference beam to an optical information recording medium that has a diffraction grating and an information recording layer by using interference fringes produced due to interference between the both beams which are converted from an irradiation beam for recording or reproduction and that guides a servo irradiation beam into the diffraction grating and causes the servo irradiation beam to be transmitted through the diffraction grating, a photodetector that detects a diffracted beam diffracted by the diffraction grating and transmitted therethrough, and an adjusting unit that controls a drive unit to adjust a position or an angle between the optical information recording medium and the optical mechanism based on the intensity of the detected diffracted beam.

Abstract: A holographic storage and reproduction system and method with a servo are provided, wherein a servo mechanism is provided, such that the holographic interferogram is continuously stored in the holographic recording medium. When a reproduced signal is to be obtained, it can be retrieved quickly and accurately through the servo mechanism. Also, the intensity distribution of the reference light reflected by the holographic recording medium can be monitored and controlled, such that the relative distance and oblique angle between the storage and reproduction system and the holographic recording medium are analyzed and adjusted.

Abstract: A method writes at least a group of holograms in a predetermined pattern in the holographic storage medium, and writes a directory hologram which relates to the holograms of the group to form an anchor location of the predetermined pattern. Further, a directory comprising the directory hologram is stored in a memory, and a read operation of at least one hologram of a group is initiated with an access for the directory hologram of the group at the anchor location; reading the accessed hologram, employing a matched filter to cross-correlate the read accessed hologram with an ideal version of the directory hologram derived from the directory stored in the memory; and determining whether the read accessed hologram is the directory hologram of the group.

Abstract: A holographic memory storage device that uses a photorefractive crystal for storing data is disclosed. The device uses angle-multiplexing in order to store and retrieve page data and sub page data. MEMS devices are used in order to provide individual sector addressing.

Abstract: The present invention relates to a method for performing pre-exposure and curing of a photo-sensitive material for optical data storage, in particular for holographic data storage, and to an apparatus for writing to optical storage media using such method. According to the invention, for pre-exposure and/or curing of an optical storage medium the optical storage medium is illuminated by a coherent light beam emitted by a light source, which is also used for data recording. Pre-exposure and/or curing is performed in one or more exposure steps, in which the coherent light beam carries a data pattern, the exposure dose for each exposure step being smaller than a minimum dose such that the diffraction efficiency of the recorded data pattern is too low to distinguish data from noise.

Abstract: Disclosed is an arrangement that enables to keep a relative positional relation between a beam for servo control and a beam for information recording/reproduction constant concerning focusing control and tracking control, even if the two beams are different from each other. An optical storage medium has a reflection surface for reflecting a first beam having a first wavelength, and reflecting a second beam having a second wavelength different from the first wavelength; and an information storage layer for recording information as an interference pattern by incidence of the first beam, or reproducing the information from a wave surface based on the interference pattern. The reflection surface is formed with plural marks or guide grooves usable in a tracking operation or a focusing operation by irradiation of the second beam.

Abstract: A hologram disc reading and writing apparatus including a signal light source module, a beam splitter, a reference/reading light source, a reflector, and an optical reading head and a hologram disc reading apparatus are provided. A signal light beam emitted from the signal light source module is transmitted to a data region of a hologram disc through the beam splitter. The reference/reading light source, the signal light source module, and the optical reading head are disposed at the same side of the hologram disc. The reflector is disposed at the other side. A spherical wave light beam emitted from the reference/reading light source is transmitted through the data region and reflected by the reflector to form a phase conjugate light beam transmitted to and through the data region. The phase conjugate light beam is transformed to a data light beam transmitted to the optical reading head through the beam splitter.

Abstract: A holographic storage and regeneration system includes a holographic recording medium, a light source, a spatial light modulator, and a conjugate servo light guidance portion. The light source generates a signal light and a reference light. The spatial light modulator modulates the incident signal light and makes it incident onto the medium along the incident direction of the signal light. The guidance portion guides a reference light to incident onto the medium in one direction and reflects it in another direction. A reference light and a signal light interfere with each other to produce a holographic interference fringe. The reflected reference light is guided into a first image sensor to be used to analyze the incident angle of the reference light. When the reference light incidents onto the fringe of the medium through the guidance portion in a reverse direction relative to another direction, a conjugate regenerated light is generated.

Abstract: There are provided an optical data storage medium and methods of optical data storage using the same. The optical data storage medium comprises a non-linear sensitizer capable of absorbing actinic radiation to cause upper triplet energy transfer to a reactant that undergoes a photochemical change upon triplet excitation.

Abstract: Provided are optical information processing apparatus and method. In the optical information processing apparatus and method, when the recording regions in which optical information is recorded in an angular multiplexing scheme overlap with each other, a recording angle and a recording position for optical information is adjusted so as to improve reproducing efficiency of readout beams reproduced from the overlap recording regions, so that heights of “null” for diffraction energy reproduced from the recording regions and overlap recording regions can be lowered. Accordingly, it is possible to reduce crosstalk noise during the recording and producing of the optical information and to improve optical information recording quality and reproducing efficiency.

Abstract: An initialization apparatus that has a simplified configuration and that forms an initial hologram in an information recording medium is provided. An initialization apparatus (10) rotates an optical disk (100) and emits blue light beams (Lb1) and (Lb2) to either side of the optical disk (100) while causing a red light beam (Lr1) to follow a track formed in a reference layer (102). Thus, the initialization apparatus (10) can perform an initialization process in which a linear initial hologram IH is formed in a recording layer (101) in a spiral pattern that corresponds to the track formed in a reference layer (102). Accordingly, the initialization apparatus (10) can form a planar initial hologram layer (YH) with significantly reduced optical energy or thermal energy emitted to the optical disk (100) at one time.

Abstract: A method is disclosed to store information in a holographic data storage medium. The method provides a hologram comprising an alignment pattern, and disposes that hologram into a holographic data storage medium during manufacture.

Abstract: A holographic data storage system that includes a write head that includes a pixellated spatial light modulator and a separate or integral phase mask that varies the phase depending on the location in the phase mask that light passes through. The phase variation can be changed over time in a random, pseudo-random, or predetermined fashion. The spatial light modulator and phase mask can be implemented in a liquid crystal SLM (nematic, ferroeleletric, or other), in a DMD SLM, in a magneto-optical SLM, or in any other suitable manner.

Abstract: A holographic recording apparatus causes reference light and information light to interfere with each other, and records the interference pattern in a recording medium. The holographic recording apparatus has an objective lens and a focus position controller. The objective lens focuses both the reference light and the information light at a focus position of the recording medium. The focus position controller changes the focus position into a predetermined position on the light path of the reference light.

Abstract: The present invention provides an optical recording method and an optical recording apparatus for holographically recording information allowing for reductions in uneven consumption of the material through the thickness of a recording layer during recording to achieve high density recording and an increased recording capacity, an optical recording medium, and an optical reproducing method and an optical reproducing apparatus using the optical recording method. The optical recording method includes irradiating the optical recording medium with an information beam and a reference beam, dividing at least one of the information beam and the reference beam into two or more between a light source thereof and an optical recording medium, and adjusting the optical path lengths of the divided information beams and reference beams so that they focus on points different from each other through the thickness of the recording layer.

Abstract: An optical information recording medium in which a inner layer is sandwiched between supporting plates and a number of recording portions formed of a recording material capable of recording information in the form of a hologram are rotatably arranged in the inner layer. The recording portion is rotated by electrifying its surface and an information beam and a reference beam are directed onto it from different angles to carry out angle multiplex recording. The surface of the recording portion is color coded with at least two colors. The color coding and rotation of the recording portions allow characters or images to be displayed. Electronic equipment using such an optical information recording medium is provided.

Abstract: The present invention relates to a holographic storage system, and more specifically to a holographic storage system using a phase spatial light modulator. According to the invention a holographic storage system with a phase SLM for imprinting a 2-dimensional phase data pattern onto an object beam includes a common path interferometer for converting the phase data pattern of the object beam into an intensity data pattern.

Abstract: An optical storage system includes a frame (e.g., a rack-mount drawer), an environmental assembly (e.g., a power and cooling subsystem) supported by the frame, and a set of optical storage devices coupled to the environmental assembly. Each optical storage device has a base, a storage medium (e.g., a sphere-shaped holographic data storage structure) disposed on the base, and an optical assembly coupled to the base. The storage medium has a curved surface configured to store data in a digital manner thereon. The optical assembly is configured to optically write the data to and read the data from the curved surface of the storage medium.

Abstract: A recording and reproducing apparatus for recording data to and reproducing data from a hologram recording medium is provided. The recording and reproducing apparatus includes a light emitting unit for emitting light to be directed to the recording medium set at a predetermined position, a spatial light modulation unit for performing spatial light modulation on incident light by pixels, an image sensor for receiving incident light by pixels and converting the incident light into an electrical signal, an optical system for guiding the light emitted by the light emitting unit to the recording medium via the spatial light modulation unit while guiding, to the image sensor, light reflected from the recording medium in response to the light emitted by the light emitting unit, and a determination unit for controlling the spatial light modulation unit.

Abstract: A data reading method used in a reading device for reading a holographic storage medium is provided. The holographic storage medium has several data areas. Each data area has several data pages, and each data page forms a data image that has at least one reserved block pattern on the reading device. The reserved block pattern of the data image corresponding to a first data page is searched within a first searching region to obtain a first pattern position. The reserved block pattern of the data image corresponding to a second data page is searched within a second searching region to obtain a second pattern position. A third searching position is then determined according to the first and second pattern positions. The reserved block pattern of the data image corresponding to a third data page is searched within a third searching region whose center is at the third searching position.

Abstract: A method for acquiring an optimum position of a reserved block in a holographic storage system is provided. Firstly, an initial offset error between an initial reserved block and its two nearest neighbors is computed. Then, according to a dynamically adjustable modified centroid function ??, a second reserved block is obtained by interpolating the covariance values associated with the initial reserved block and the respective two nearest neighbors. Afterwards, the optimum position of the reserved block is acquired according to the second reserved block and the initial offset error.

Abstract: There is provided a data playback method including: acquiring first image data by illuminating reference light for reading onto an optical recording medium on which a hologram has been recorded by Fourier transforming and simultaneously illuminating reference light and signal light expressing digital data as a light-and-dark image, and detecting an inverse Fourier-transform image of diffracted light which is diffracted by the recorded hologram; acquiring second image data, which is a reversal image of the first image data, by generating combined light by combining the diffracted light and a dc component whose phase is different than a phase of a dc component of the signal light included in the diffracted light, and detecting an inverse Fourier-transform image of the combined light; and computing a difference in luminance for each pixel of the light-and-dark image, by carrying out computing processing by using the first and second image data.

Abstract: A holographic recording medium in which information can be reproduced by phase conjugate beam without requiring a mirror for obtaining the phase conjugate beam and its driving part and recording density is not reduced. The recording medium includes a recording layer in which an interference pattern is recorded and a light absorption/transmission layer which can be reversibly changed to be in a first state where signal beam and reference beam passed through the recording layer are absorbed at the time of recording of information and a second state where the reference beam is transmitted at the time of reproduction of information, and the reference beam transmitted through the light absorption/transmission layer is reflected by a reflection layer to produce the phase conjugate beam.

Abstract: An optical-pickup hologram element has six regions on an x-y plane, divided as follows: the first region with a first line (an x-axis) and a second line that connects points (?xa, 0) and (?xb, yb); the second region with the first and second lines and a third line connecting points (xa, 0) and (xb, yb); the third region with the first and third lines; the fourth region with the first line and a fourth line connecting the point (xa, 0) and a point (xb, ?yb); the fifth region with the first and fourth lines and a fifth line connecting the point (?xa, 0) and a point (?xb, ?yb); and the sixth region with the first and fifth lines (xa<xb and ?xb<?xa). The second and fifth, and the other regions are given astigmatism at different angles to the second line.

Abstract: A hologram recording device that records a hologram by passing recording light and reference light through the same objective lens and irradiating a recording medium, includes: a light splitter for dividing light from a light source into the recording light and the reference light; a light combining member for combining the recording light and the reference light, which have been divided by the light splitter, so as to be coaxial, and causing these light beams to advance to the objective lens; first and second lenses, positioned on an optical paths of the recording light and reference light, between the light splitter and the light combining member; a first aperture that narrows the recording light which has passed through the first lens; and, a second aperture that narrows the reference light which has passed through the second lens, the first and second lenses being configured to have different optical magnifications.

Abstract: Techniques are described that can be used to store information onto a holographic storage medium. Techniques are described that can be used to access information from a holographic storage medium. Multiple beam sources and multiple detectors can be used to store and/or read information. At least one detector can be available to read information available from a beam reflected from the medium. Multiple read and/or write operations may take place at substantially the same time.

Abstract: A hologram device includes: a light source for applying light to a hologram recording medium having a recording layer in which information recording is performed by interference fringes between signal light and reference light; a spatial modulation unit that generates the signal light and/or the reference light and generates a marker light in a predetermined position within an incident surface of the light from the light source by performing spatial light modulation on the light from the light source; a light applying unit that applies the light subjected to spatial light modulation by the spatial light modulation unit to the hologram recording medium via an objective lens; a light receiving unit that receives the light applied via the objective lens through the hologram recording medium; and a tilt detection unit that obtains a tilt error signal representing an error from an ideal angle of a tilt angle as an incident angle of the applied light via the objective lens to an information recording surface of the

Abstract: A method is disclosed to determine an optimal power level to encode information holographically. The method sets (N) evaluation power levels, displays an evaluation image on a spatial light modulator. For each value of (i), the method energizes a light source using the (i)th power level, generates the (i)th reference beam, generates the (i)th carrier beam, forms the (i)th data beam comprising the evaluation image, forms the (i)th hologram using the (i)th reference beam and the (i)th data beam, and encodes the (i)th hologram in a holographic data storage medium, where (i) is greater than or equal to 1 and less than or equal to (N).

Abstract: An optical recording device includes a light source, a light-converging optical system, a moving unit, detection unit, and an acquisition unit. In the optical recording device, interference fringes from a recording light are shift multi-recorded as a plurality of pages of holograms within each of a plurality of planes corresponding to a plurality of convergence positions based on light exposure amount of each page, acquired by the acquisition unit, for each of the convergence positions.

Abstract: A hologram recording/reconstructing apparatus includes a spatial modulator in which a reference beam region and a reconstruction beam region are formed, and a controller configured to control a range of the reference beam region and a range of the reconstruction beam region. According to a temperature of a hologram recording medium during recording, the controller sets the range of the reference beam region to a first predetermined range and thereby sets a range of an incident angle of a reference beam on the hologram recording medium to a first predetermined angle range. According to a temperature of the hologram recording medium during reconstruction of recorded data, the controller sets the range of the reconstruction beam region to a second predetermined range and thereby sets a range of an incident angle of a reconstruction beam on the hologram recording medium to a second predetermined angle range.

Abstract: An optical information recording method includes the following steps. A converting step is converting a light beam into an information beam carrying information by using a spatial beam modulator. A focusing step is focusing the information beam on an optical information recording medium including an information recording layer. An irradiating step is irradiating the optical information recording medium with a reference beam and the information beam so that the reference beam and the information beam intersect with each other on the information recording layer by using an optical component. A rotating step is rotating the optical information recording medium or the optical component by using a drive unit for performing angle-multiplex recording. A management information recording step is recording management information at two or more relative angles having an angle interval smaller than twice at least a first null angle.

Abstract: An information recording/reproducing apparatus can suppress generation of stray light and prevent aggravation of the SN (signal to noise) ratio at the time of reproduction. If the angle of incidence of reference beam relative to the information recording medium (transmission-type disk 119 or reflection-type disk 213) at the time of recording is ?1, the angle of incidence of reference beam relative to the information recording medium at the time of reproduction is ?2 and the angle of incidence of reference beam reentering the information recording medium relative to the information recording medium at the time of reproduction is ?3, the angle of the galvano mirror for changing the angle of incidence of reference beam and the angle of the galvano mirror for reentering reference beam into the information recording medium are controlled so as to establish relationships of ?1??2 and ?1=?3.

Abstract: A hologram recorder/player includes recording beam modulation controller which causes a spatial light modulator to modulate the recording beam in such a way that a hologram is recorded in a plurality of blocks in a unit recording region and that each of the blocks includes recording information (DATA) and error correction code, at a time of recording. The hologram recorder/player includes incident angle variable controller which varies a reference beam incident angle to a plurality of predetermined angles with respect to the unit recording region. The recording beam modulation controller causes the modulation of the recording beam in such a way that a different hologram is generated for a page each time the reference beam incident angle is varied and that the hologram in each page is recorded in a plurality of the blocks.

Abstract: The present invention relates to an apparatus for reading from and/or writing to holographic storage media, and more specifically to an apparatus for reading from and/or writing to holographic storage media having an apodization filter. According to the invention, an apparatus for reading from and/or writing to a holographic storage medium, with a collinear split aperture arrangement of a reference beam and an object beam or a reconstructed object beam, includes an apodization filter for the reference beam.

Abstract: A method to provide data storage services using one or more holographic data storage media disposed in a holographic data storage system operated by a data storage services provider, wherein the holographic data storage system comprises a light source, a spatial light modulator, and a plurality of holographic data storage media, wherein the method receives information provided by the data storage services customer, allocates a first holographic data storage medium for exclusive storage of information provided by the data storage services customer, defines an outer storage portion of the first allocated holographic data storage medium, and stores the information as one or more holograms encoded in the outer storage portion of the first holographic data storage medium.

Abstract: An optical information reproducing apparatus using holography is provided. The holographic optical information reproducing apparatus includes an objective lens irradiating a reference beam to a predetermined position on a recording medium and receiving a reproducing beam reproduced from the recording medium, an optical information detector detecting the reproducing beam passing through the objective lens, a driving unit changing a distance between the optical information detector and the objective lens and an image adjusting unit adjusting magnification and a focus between an output image resulting from the reproducing beam passing through the objective lens and a detected image detected by the optical information detector with a variation in distance between the optical information detector and the objective lens.

Abstract: Provided are an optical information recording/reproducing apparatus and method capable of managing a wavelength of a light source when information is recorded/reproduced by utilizing holography, and limiting a wavelength of an interference fringe in a medium, and an optical information recording medium. For information recording/reproducing relative to an optical information recording medium by a pickup, a wavelength detector circuit detects a reference wavelength recorded in a storage area of the optical information recording medium, in accordance with the detected reference wavelength, a controller adjusts a wavelength of a light source of the pickup to have an optimum wavelength, and if a temperature detected with a temperature sensor indicates a predetermined change, readjusts the wavelength of the light source of the pickup to have an optimum wavelength.

Abstract: A hologram recording apparatus that records a hologram on a recording layer of a hologram recording medium by causing interference between signal light modulated in accordance with record data and reference light from the same light source as that of the signal light is provided. The apparatus includes: a signal light spatial light modulating section that displays a signal light pattern for causing the signal light; a reference light spatial light modulating section that displays a reference light pattern for causing the reference light; a control section that controls the form of the signal light pattern to be displayed on the signal light spatial light modulating section and the form of the reference light pattern to be displayed on the reference light spatial light modulating section and controls optical energy of the signal light and reference light; and a temperature sensor that senses the temperature of the hologram recording medium.